The purpose of this application for a K01 Mentored Research Scientist Development Award is to provide the candidate with mentoring that will promote her development as an independent investigator in the area of HIV prevention with a focus on using advanced statistical and methodological tools to increase understanding of behavioral change and contribute to intervention development. This goal will be achieved via a five-year mentored training plan and complementary research plan. Aims of the training plan are to: (1) learn to apply the technique of integrative data analysis (IDA), a technique for combining multiple, independent datasets to increase statistical power and sample diversity; increase skills related to other advanced statistical techniques that can aid in the analysis of data from randomized controlled trials (2) (RCTs); (3) increase theoretical and applied knowledge of sexual risk reduction interventions with high-risk populations ; and (4) strengthen manuscript preparation and grant writing skills. These goals will be achieved through mentorship from and collaboration with leading experts in quantitative methods, biostatistics in the context of HIV prevention, and HIV interventions, as well as through formal coursework, workshops, seminars, and direct participation in research activities. Knowledge gained via the training plan will be augmented by the proposed research. The overall aim of the proposed research is employ IDA to combine data from four RCTs conducted at sexually transmitted infection (STI) clinics. The resultant data set, including longitudinal data from 3,704 patients, will allow the testing of critcal hypotheses and the evaluation of constructs hypothesized to influence sexual risk reduction following intervention. Results will identify key targets for brief risk reduction interventions. Te specific aims of the proposed research are (1) to integrate data from RCTs of sexual risk reduction interventions to extract overall trajectories of sexual risk behavior prior to and following intervention, (2) to determine mechanisms of change in sexual risk behavior, and (3) to identify factors associated with differential response to intervention. The proposed research will show patterns of intervention-related behavior change across multiple trials and identify key variables associated with sexual risk reduction, suggesting targets for more effective, cost-efficient brief interventions that may reduce rates of STIs including HIV, and will generate conference presentations, journal K-award, the candidate will emerge as an independent investigator with expertise in sophisticated statistical methodologies ready to make unique contributions to the field of HIV prevention.